The invention relates to a device for optical communication between electronic modules comprising an optically conducting rod, having first and second ends, designed to be optically coupled, by lateral coupling, to lateral electronic modules arranged laterally along the rod, and comprising lateral reflecting means arranged over a longitudinal part of the external surface of the rod opposite the lateral modules.
A large number of devices exist enabling optical interconnection of electronic modules.
In a first type of device, as described in the document EP-A-587,066 for example, an optical communication bus is formed by a plurality of modular electrical equipment units arranged side by side. Each unit is equipped on one side face with an opto-electronic receiver and on the opposite side face with an electro-optical transmitter electrically connected to the receiver. Each unit can thus communicate optically with the adjacent units. This type of device presents a major drawback in that, if one of the units fails, the communication chain is broken.
Backplane optical busses also exist, generally constituted by a plate made of glass or transparent plastic material comprising means for optical coupling with printed circuit boards, each board comprising at least one electro-optical transmitter and one opto-electronic receiver. Various coupling means, arranged on the face of the bus adjacent to the printed circuit boards, have been described, in particular windows made of a light-absorbing material (WO-A-8,503,179), grooves (GB-A-2,208,566) and diffraction networks (U.S. Pat. No. 5,091,985). U.S. Pat. No. 4,744,617 describes an optical bus of circular, square or polygonal cross-section, comprising as coupling elements inclined reflecting surfaces formed in the face of the bus opposite the printed circuit boards. In these different devices, the coupling elements are punctual and are fitted at predefined locations, associated to each of the printed circuit boards. The number of printed circuit boards and their locations are thus predefined.
In the document EP-A-249,746, a multimode optical fiber comprising a diffusing core enables optical communication between transmitter and receiver stations that are coupled laterally thereto. The stations can be arranged at any location along the optical fiber. In this device, optical lenses fitted between the fiber and each of the stations have to be placed in the immediate proximity of the fiber. The radial positioning of the lenses and of the associated stations is relatively critical.
In the document WO-A-9,839,861 a bi-directional optical transmission system between electronic components uses light diffused in the air inside a channel bounded by the optically reflecting internal surface of a U-shaped enclosure made of metal or plastic. The opto-electronic transmitter and receiver elements of the electronic components can be arranged at any location along the channel, but must on the other hand advance inside the channel. The distance of these components to the channel is therefore precisely defined.